mariadb/mysql-test/suite/innodb/r/innodb_bug14147491.result
Marko Mäkelä 14685b10df MDEV-32050: Deprecate&ignore innodb_purge_rseg_truncate_frequency
The motivation of introducing the parameter
innodb_purge_rseg_truncate_frequency in
mysql/mysql-server@28bbd66ea5 and
mysql/mysql-server@8fc2120fed
seems to have been to avoid stalls due to freeing undo log pages
or truncating undo log tablespaces. In MariaDB Server,
innodb_undo_log_truncate=ON should be a much lighter operation
than in MySQL, because it will not involve any log checkpoint.

Another source of performance stalls should be
trx_purge_truncate_rseg_history(), which is shrinking the history list
by freeing the undo log pages whose undo records have been purged.
To alleviate that, we will introduce a purge_truncation_task that will
offload this from the purge_coordinator_task. In that way, the next
innodb_purge_batch_size pages may be parsed and purged while the pages
from the previous batch are being freed and the history list being shrunk.

The processing of innodb_undo_log_truncate=ON will still remain the
responsibility of the purge_coordinator_task.

purge_coordinator_state::count: Remove. We will ignore
innodb_purge_rseg_truncate_frequency, and act as if it had been
set to 1 (the maximum shrinking frequency).

purge_coordinator_state::do_purge(): Invoke an asynchronous task
purge_truncation_callback() to free the undo log pages.

purge_sys_t::iterator::free_history(): Free those undo log pages
that have been processed. This used to be a part of
trx_purge_truncate_history().

purge_sys_t::clone_end_view(): Take a new value of purge_sys.head
as a parameter, so that it will be updated while holding exclusive
purge_sys.latch. This is needed for race-free access to the field
in purge_truncation_callback().

Reviewed by: Vladislav Lesin
2023-10-25 09:11:58 +03:00

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# Ensure that purge will not crash on the table after we corrupt it.
SET GLOBAL innodb_fast_shutdown=0;
# Create and populate the table to be corrupted
set global innodb_file_per_table=ON;
CREATE TABLE t1 (a INT AUTO_INCREMENT PRIMARY KEY, b TEXT) ENGINE=InnoDB;
INSERT INTO t1 (b) VALUES ('corrupt me');
INSERT INTO t1 (b) VALUES ('corrupt me');
# Corrupt the table
Munged a string.
Munged a string.
# restart
# Now t1 is corrupted but we should not crash
SELECT * FROM t1;
Got one of the listed errors
INSERT INTO t1(b) VALUES('abcdef');
Got one of the listed errors
UPDATE t1 set b = 'deadbeef' where a = 1;
Got one of the listed errors
# Cleanup, this must be possible
DROP TABLE t1;